Circumferentially contractible clamps are widely used to clamp pipe members or the like in aligned end-to-end relation. Such clamps usually consist of a band or strap adapted to encircle the end flanges of the pipe members to be connected and an actuator located on the ends of the band to facilitate contraction and expansion of the band. Tightening of the actuator draws the ends of the band toward each other constricting the band about the flanges to provide the effective clamping forces necessary to maintain the pipes together. Typical examples of these types of clamps are shown in U.S. Pat. Nos. 4,563,795; and 4,739,542.
The aforementioned clamps are relatively inexpensive to manufacture, simple to use, and are dependable under heavy loading conditions. However, such clamps are often utilized with pipes which are not as durable as the clamps, and upon the pipes being subjected to exceptional bending or tensile forces, it is known for the clamps to maintain the flanges together while the pipes themselves have fractured or sustained extensive damage rendering them permanently useless. Preferably, since the pipes are more expensive than the clamp, upon the pipes being subjected to exceptional loading conditions the clamp itself should release allowing the pipes to separate without damage, but heretofore, a clamp of this type has not been available for use.
It is an object of the invention to provide a circumferentially contractible clamp for securing a pair of pipe members in aligned end-to-end relation wherein the clamp is dependable under heavy loading conditions, yet upon the pipes being subjected to exceptional tensile or bending forces, the clamp will fracture releasing the pipe ends to prevent the pipes from being damaged.
Another object of the invention is to provide a frangible, contractible clamp having a band adapted to encircle aligned flange pipe ends and a band constricting actuator for circumferentially contracting the band wherein the band consists of retainer elements fastened together by frangible fasteners which will fracture upon a predetermined axial loading condition imposed on the clamp causing the band to disengage the flange to allow the pipes to separate without damage.
Yet another object of the invention is to provide a frangible, circumferentially contractible clamp which is capable of fracturing upon being subjected to predetermined axial loading conditions wherein the clamp is of economical manufacture, dependable in operation, and simple and efficient to use.
In the practice of the invention the frangible clamp includes a band adapted to embrace end flanges of a pair of pipe members to be connected and a band constricting actuator to facilitate contraction and expansion of the band. The band includes a generally circular outer strap and a plurality of inner arcuate segments, and the segments consist of a pair of retainer halves each having a base and a flare portion depending from the base adapted to engage the flange end of one of the pipes. The retainer halves are fastened together at their bases by frangible fasteners in the form of rivets whereby the flare portions extend in a common direction defining an envelope conforming to the opposed flanges, and the same fasteners are also utilized to mount the retainer halves to the outer strap.
In use, the clamp is positioned on the opposed flanges and the actuator is tightened until the desired band constriction is achieved, in which case each of the flares abut with one of the pipe flanges to secure the flanges together. Under normal operating conditions the frangible fasteners are of sufficient strength to maintain the retainer halves together and secure the pipes in end-to-end relation, but upon the pipe members being subjected to exceptional bending or tension forces the frangible fasteners will fracture permitting the retainer halves to separate and disengage the flanges. This permits the flanges to separate cleanly and prevents the pipes from sustaining serious damage possibly rendering them permanently useless.